Modelos de dispersão para extremos de precipitação. Estudo de caso: o nordeste do Brasil

In this thesis used four different methods in order to diagnose the precipitation extremes on Northeastern Brazil (NEB): Generalized Linear Model s via logistic regression and Poisson, extreme value theory analysis via generalized extre me value (GEV) and generalized Pareto (GPD) distributions and Vectorial Generalized Linea r Models via GEV (MVLG GEV). The logistic regression and Poisson models were used to identify the interactions between the precipitation extremes and other variables based on the odds ratios and relative risks. It was found that the outgoing longwave radiation was the indicator variable for the occurrence of extreme precipitation on eastern, northern and semi arid NEB, and the relative humidity was verified on southern NEB. The GEV and GPD distribut ions (based on the 95th percentile) showed that the location and scale parameters were presented the maximum on the eastern and northern coast NEB, the GEV verified a maximum core on western of Pernambuco influenced by weather systems and topography. The GEV and GPD shape parameter, for most regions the data fitted by Weibull negative an d Beta distributions (ξ < 0) , respectively. The levels and return periods of GEV (GPD) on north ern Maranhão (centerrn of Bahia) may occur at least an extreme precipitation event excee ding over of 160.9 mm /day (192.3 mm / day) on next 30 years. The MVLG GEV model found tha t the zonal and meridional wind components, evaporation and Atlantic and Pacific se a surface temperature boost the precipitation extremes. The GEV parameters show the following results: a) location ( ), the highest value was 88.26 ± 6.42 mm on northern Maran hão; b) scale ( σ ), most regions showed positive values, except on southern of Maranhão; an d c) shape ( ξ ), most of the selected regions were adjusted by the Weibull negative distr ibution ( ξ < 0 ). The southern Maranhão and southern Bahia have greater accuracy. The level period, it was estimated that the centern of Bahia may occur at least an extreme precipitatio n event equal to or exceeding over 571.2 mm/day on next 30 years.

Sismicidade e esforços tectônicos na zona sísmica Acaraú, Nordeste do Brasil

Inside the Borborema Province the Northwestern Ceará (NC) is one of the most seismic active regions. There are reports of an earthquake occurred in 1810 in the Granja town. On January, 2008 the seismic activity in NC has increased and it was deployed a seismographic network with 11 digital stations. In 2009, another earthquake sequence began and it was deployed another seismographic network in the Santana do Acaraú town with 6 stations. This thesis presents the results obtained by analyzing the data recorded in these two networks. The epicentral areas are located near the northeastern part of the Transbrasiliano Lineament, a shear zone with NE-SW-trending that cuts the study area. The hypocenters are located between 1km and 8km. The strike-slip focal mechanisms were found, which is predominant in the Borborema Province. An integration of seismological, geological and geophysical data was performed and it show that the seismogenic faults found are oriented in the same direction to the local brittle structures observed in field and magnetic lineaments. The SHmax (maximum compressional stress) direction in NC was estimated using an inversion of seven focal mechanisms. The horizontal maximum compression stress (σ1 = 300°) with orientation NW-SE and extension (σ3 = 210°) with NE-SW and σ2 vertical. These results are consistent with results of previous studies. The seismic activity recorded in NC is not related to a possible reactivation of the Transbrasiliano Lineament, by now.

A plasticidade acústica de uma população de Boto - Cinza, Sotalia Guianensis (Van Banédén, 1864) (Cetacea, Delphinidae), na região Nordeste do Brasil

The environmental characteristics can modify the acoustics of a species due to habitat, time of day and year. Therefore, this study investigated the relationships between seasons, tide, daily cycle of tides, times of day and different habitat and noise emission of S. guianensis. Sound recordings occurred in the Curral’s Cove and Lagoon Complex of Guaraíras (CLG) in the municipality of Tibau do Sul/RN. Whistles are emitted with lower frequency during rainy season and spring tide while clicks are higher; whistles, clicks and calls have higher frequency during ebb tide. These modifications can be related with turbidity and prey availability. The whistles and clicks occurrence are higher at night probably because luminosity is lower. Furthermore, the whistles and clicks frequency reduction overnight allows the sound to travel longer distance and helps the view which is limited; but the minimum frequency increase was needed to catch the prey. The low occurrence of calls could be related to the small group size. The acoustic changes at night may be partly influenced by light levels as prey availability that is larger in this period. Whistle frequencies and click initial frequency are higher in CLG than Curral’s cove that permitted good precision. However, click central frequency is lower and may be connected to tracking the area. Several factors may be associated with such modifications as background noise, bottom and others. This study supports the hypothesis that S. guianensis presents an acoustic plasticity according to the local conditions where the species is embedded and adapts to the environmental changes.

Análise estratigráfica de subsuperfície do Devoniano Inferior da Bacia do Rio do Peixe, Nordeste do Brasil

Subsurface stratigraphic analysis of Devonian strata from the Rio do Peixe Basin, newly recognized by palynological studies, has resulted in the identification of two new lithostratigraphic units assembled in the Santa Helena Group. The Pilões Formation, the lower unit, is composed mainly of dark mudstones and medium-tovery fine-grained sandstones, with minor conglomerates and breccias. The Triunfo Formation, the upper unit, comprises whitish grey, kaolinitic, coarse-grained to conglomeratic, cross stratified sandstones and conglomerates, with interbedded mudstones and fine-grained sandstones. These units were characterized using cores, sidewall and cuttings samples, conventional logs and image log, from three wells drilled by PETROBRAS, and 3D seismic data. The Pilões Formation is interpreted as prodeltaic facies, with lesser associated subaqueous talus, debrite and sandy turbidite lobe facies, distal part of fandelta and braided fluviodeltaic facies of Triunfo Formation. The Santa Helena Group corresponds to the Lower Devonian tectono-sequence deposited in a NW-SE-trending graben during a transgressiveregressive cycle. With 343 meters of thickness (isochore) in well 1-PIL-1-PB (Pilões 1), this sequence has a non-conformity at the lower boundary and its upper boundary is an unconformity with the Lower Cretaceous tectono-sequence (Rio do Peixe Group), that represents a hiatus of about 265 million years. Ignimbrites and coignimbrite breccias (Poço da Jurema volcanic breccia), related to an unknown pyroclastic volcanic event, were recognized at the northern margin of the Sousa halfgraben. Evidence from well data suggests that this event is coeval with the Devonian graben filling. The present study indicates a polyhistorical tectono-volcanosedimentary evolution of the basin. This lithostratigraphic update brings new perspectives for geological research in the Rio do Peixe Basin, as well as in other inland basins of the Northeastern of Brazil. The results of the research also contribute to the kwnoledge of the Borborema Province and western Gondwana paleogeography during the Early Devonian.

Mortalidade segundo sua causa de morte e seus determinantes: uma análise para as capitais brasileiras e municípios do nordeste do Brasil, 2000 e 2010

This dissertation considered the development of two papers, both related to mortality in Brazil. In the first article, "The context of mortality according to the three broad groups of causes of death in Brazilian capitals, 2000 and 2010", the objective was to analyze the mortality rate according to the three major groups of causes of death in Brazilian capitals. In the second article, "Typology and characteristics of mortality from external causes in the municipalities in the Northeast of Brazil, 2000 and 2010", it was built up a typology for the Northeastern municipalities taking into account information on mortality from external causes and a set of indicators related to socioeconomic, demographic, and infrastructure aspects of such municipalities, both articles for the years 2000 and 2010. Thus, we used data from the Mortality Information System of the Ministry of Health. Furthermore, it was used information from the Demographic Census for those years. The variables relating to socioeconomic and demographic conditions used in this study were those available on the home page of the United Nations Program for Development. The variables relating to socioeconomic and demographic conditions used in this study were those available on the home page of the United Nations Program for Development. Was used in Article 1 the pro-rata distribution method to accomplish the redistribution of ill-defined causes. Moreover, made use of the technique of cluster analysis with the aim of grouping the capital that had proportions of deaths from ill-defined causes similar to each other. Already in Section 2, we used the technique of Empirical Bayesian estimation; spatial statistics technique; and finally, the Grade of Membership method to find types of municipalities from information on mortality from external causes associated with socioeconomic, demographic and infrastructure variables. As the main results, it stands out in Article 1, in relation to data quality, we observed the formation of four groups of similar capital between themselves, as the proportion of illdefined causes. Regarding the behavior of mortality, according to the three major groups of causes of death, it was noted both for 2000 and for 2010 the prevalence of deaths from noncommunicable diseases for both sexes, although the reduction was identified rates in some of the capitals. Communicable diseases stood out as the second cause of death among women. Also, we found that deaths due to external causes are responsible for the second cause of death among men, as well as presenting an increase among women. As for the Article 2, stands out, in general, not just an extension of mortality from external causes in the municipalities, as well as an enlargement of the configurator stain existence of external cause deaths for the whole area of Northeast. Regarding the typology of municipalities, three vi extreme profiles were buit: the profile 1, which comprises municipalities with high rates of mortality from external causes and the best social indicators; the profile 2, that was composed of municipalities that are characterized by having low mortality rates from external causes and the lowest social indicators; and the profile 3, that brings together municipalities with intermediate mortality rates and median values considered in relation to social indicators. Although we have not seen changes in the characteristics of the profiles, we observed an increase in the proportion of municipalities that belong to the extreme profile 3, taking into account the mixed profiles.

Parâmetros biológicos de Herpsilochmus pectoralis Sclater 1857 (Aves: Thamnophilidae) em fragmentos de mata atlântica do Nordeste do Brasil

The study of birds represents an important tool for the understanding of the processes involved in behavioral and morphological patterns. The species we have studied belongs to Thamnophilidae family, the third largest family restricted to the Neotropic ecozone. They are popularly known as antbirds and comprise 209 species. A large portion of the species has cryptic behavior, making the acoustic communication an important tool for maintaining contact among birds. Herpsilochmus pectoralis Sclater 1857 has evident sexual dimorphism, measured between 10 and 12 cm height and it is found in forest fragments in the Northeast and it is also categorized as vulnerable to extinction process. This study was conducted in three sandbank fragments on the east coast of the state of Rio Grande do Norte, Brazil. With the help of tape recordings between 2006 and 2012 it was possible to describe and characterize the sing of H. pectoralis. The sing from male birds has more and longer length than the female sing (16% of dimorphism). No differences were found in the dominant frequency between the sexes. We describe four types of calls from this species repertoire. Through capturing with ornithological nets between 2009 and 2012 it was possible to describe and compare the morphology of H. pectoralis. The species have shown lower corporal mass in the dry season. The young birds showed morphometric similarities in comparison to adults. The species has no accentuated dimorphism in their morphometric characteristics. The young ones with flying capabilities have morphometric characteristics of adults, even though they do not show a characteristic adult plumage. The moult pattern in the species is a characteristic of tropical birds, but it shows short reproductive period, typical of temperate species. Even being in the tropical region, the species suffers with seasonal rainfall, which influences their reproductive phenology and moult (remex and rectrix) cycle. Thus, this dissertation provides information on the biology of H. pectoralis to support the understanding of the relationship of this species to the environment and also to know the variations of morphology and vocal aspects, in order to understand patterns and general characteristics of Thamnophilidae.

Morfometria, variação anual no peso e demografia do Tico-tico-rei-cinza (Lanio pileatus: thraupidae) em dois ambientes de caatinga no nordeste do Brasil

The caatinga is considered the only exclusively Brazilian biome, with a total area of 735.000km². It is estimated that about 59% of this area has already been removed and only 2% are protected in conservations units. The region is characteristic by strong seasonality and heterogeneity in their environments. This paper sets generate information on morphological and population patterns Lanio pilatus in two areas of caatinga of Estação Ecológica do Seridó (ESEC – Seridó), Serra Negra do Norte - RN. Data collection was performed in six phases between July 2012 and December 2014, covering the end of the dry and rainy seasons in the region. The captures were performed with nets and individuals captured were marked with metal rings and measured (weight, wing length, tail, tarsus, culmen and tip of the bill to nostril). Through these measures, we observed that only males of open area range in weight during the dry and rainy season, youngs were significantly lower for all parameters measured, and males were larger than females in three characteristics (weight, wing length and tail) in open area and only one (wing length) in the closed area. The population parameters were generated from the mark-capture-recapture technique by program MARK, using the techniques of robust design and CJS. The survival probability of detection and population estimates varied with time. Only individuals of open area fluctuated in their estimates during the study. Overall, the environment was a great mediator of results which increases the need for more studies on the life history of the species in the region.

Um estudo sobre a variabilidade do vento no nordeste do Brasil através de métodos estatísticos e via modelos dinâmicos de meso e micro escala

The objective of this study was to determine the seasonal and interannual variability and calculate the trends of wind speed in NEB and then validate the mesoscale numerical model for after engage with the microscale numerical model in order to get the wind resource at some locations in the NEB. For this we use two data sets of wind speed (weather stations and anemometric towers) and two dynamic models; one of mesoscale and another of microscale. We use statistical tools to evaluate and validate the data obtained. The simulations of the dynamic mesoscale model were made using data assimilation methods (Newtonian Relaxation and Kalman filter). The main results show: (i) Five homogeneous groups of wind speed in the NEB with higher values in winter and spring and with lower in summer and fall; (ii) The interannual variability of the wind speed in some groups stood out with higher values; (iii) The large-scale circulation modified by the El Niño and La Niña intensified wind speed for the groups with higher values; (iv) The trend analysis showed more significant negative values for G3, G4 and G5 in all seasons and in the annual average; (v) The performance of dynamic mesoscale model showed smaller errors in the locations Paracuru and São João and major errors were observed in Triunfo; (vi) Application of the Kalman filter significantly reduce the systematic errors shown in the simulations of the dynamic mesoscale model; (vii) The wind resource indicate that Paracuru and Triunfo are favorable areas for the generation of energy, and the coupling technique after validation showed better results for Paracuru. We conclude that the objective was achieved, making it possible to identify trends in homogeneous groups of wind behavior, and to evaluate the quality of both simulations with the dynamic model of mesoscale and microscale to answer questions as necessary before planning research projects in Wind-Energy area in the NEB

Gato-do-mato-pequeno (Leopardus tigrinus) na Caatinga: ocupação e padrão de atividade de um felídeo ameaçado e pouco conhecido na floresta tropical seca do nordeste do Brasil

While the carnivores are considered regulators and structuring of natural communities are also extremely threatened by human activities. Endangered little-spotted-cat (Leopardus tigrinus) is one of the lesser known species from the Neotropical cats. In this work we investigate the occupancy and the activity pattern of L. tigrinus in Caatinga of Rio Grande do Norte testing: 1) how environmental and anthropogenic factors influence their occupation and 2) how biotic and abiotic factors influence their activity pattern. For this we raised occurrence data of species in 10 priority areas for conservation. We built hierarchical models of occupancy based on maximum likelihood to represent biological hypotheses which were ranked using the Akaike Information Criterion (AIC). According to the results the feline occupancy is more likely away from rural settlements and in areas with a higher proportion of woody vegetation. The opportunistic killing of L. tigrinus and in retaliation for poultry predation close to residential areas can explain this result; as well as more complex vegetation structure can better serve as refuge and ensure more food. Analyzing the records of the species through circular statistics we conclude that the activity pattern is mostly nocturnal, although considerable crepuscular and a small diurnal activity. L. tigrinus activity was directly affected by the availability of small terrestrial mammals, which are essentially nocturnal. In addition, the temperatures recorded in the environment directly and indirectly affect the activity of the little-spotted-cat, as also influence the activity of their potential prey. Generally, the cats were more active when possible prey were active, and this happened at night when lower temperatures are recorded. Moreover, the different lunar phases did not affect the activity pattern. The results improve the understanding of an endangered feline inhabiting the Caatinga biome, and thus can help develop conservation and management strategies, as well as in planning future research in this semi-arid ecosystem.

Impacto do Programa Saúde da Família sobre indicadores de saúde da criança em municípios de grande porte da região Nordeste do Brasil

The present study carried out in the context of the Baseline Studies of the PROESF was aimed at evaluating the impact of the Family Health Program (PSF) on indicators for child health in cities with more than 100,000 inhabitants in the Brazilian Northeast. Four cities were investigated. In each one, twenty censual sectors were selected randomly from areas covered by the PSF and compared with twenty sectors selected from areas not covered by the PSF on the basis of socioeconomic criteria. In most cases, no significant differences were found between the areas covered and not covered by the PSF. The only difference found was a significantly lower rate of hospital admissions due to diarrhea but this was on account of the Program of Community Health Agents. The PSF exerted no additional effect on the reduction of this indicator. It was also observed that the way by which the program is implemented in each city interferes directly in the results. Thus, there is no basis for considering the PSF per se ineffective or not differing from other programs with regard to its health care patterns. An evaluation of the PSF would necessarily have to include an analysis of the way the program is implemented and conducted in each case, besides considering its general socioeconomical and political characteristics.

Da casa grande ao condomínio fechado: o que mudou nas formas e modos de morar da família intergeracional no Nordeste e Sudeste do Brasil?

The focus of this study is to draw attention to the intergenerational family’s lifestyles and their various ways of cohabitation, in special to those families which are made by individuals of different generations, these families being constituted of, two or more individuals, or, two or more smaller families, which live under the same roof and have the elderly person as referential in their cohabitation. In those types of families, as for their ways of organization, it is interesting to note that the researches and productions done by inner architects and inner designers do not include this type of family arrangement because their studies do not cover this kind of structuralization nor was this type of organization put together with any of the ways of cohabitation. Therefore there is a theoretical concept void which is propositional, interventional and does not relate to the empirical reality. In observation to these remarks, the research starts a theoretic challenge of deconstruct or reconstruct our modern only habitational template, which is used today in all families configurations which out any regards to where this template will be used, unfitting to the intergenerational families who have elders. This study is then meant to give an differential analysis of the various domestic space’s templates in regards to the new families formats, their basic and special necessities, the home identities of those families which indicates the differential gap in housing and lifestyle from the higher social classes in comparison to the lower social classes. The interdisciplinary method was chosen in order to describe arrangements found in the lifestyles and the ways of cohabitation of the intergenerational families, this method is used for its knowledge base that better articulates the procedure method and the inductive reflexive approach made possible after an qualitative research. In order to accomplish that, an geographical space which tow real possibilities was selected, that is, the space where the people of great social and anthropological proximity are concentrated and the people which are the researcher kinships and friends, in between those are the habitants of Capim Macio’s, Candelária’s, Tirol’s and Petrópolis’s, neighborhoods, located in the south west zone of her home city Natal. It has been noticed that, meanwhile these intergenerational spaces do not claim their said spaces, because of their habits, necessities and relations in between generations and gender, their arrangements of said space are extremely creative. That means that alterations in the concepts of planning, construction and utilization of built spaces are imperative.

Da casa grande ao condomínio fechado: o que mudou nas formas e modos de morar da família intergeracional no Nordeste e Sudeste do Brasil?

The focus of this study is to draw attention to the intergenerational family’s lifestyles and their various ways of cohabitation, in special to those families which are made by individuals of different generations, these families being constituted of, two or more individuals, or, two or more smaller families, which live under the same roof and have the elderly person as referential in their cohabitation. In those types of families, as for their ways of organization, it is interesting to note that the researches and productions done by inner architects and inner designers do not include this type of family arrangement because their studies do not cover this kind of structuralization nor was this type of organization put together with any of the ways of cohabitation. Therefore there is a theoretical concept void which is propositional, interventional and does not relate to the empirical reality. In observation to these remarks, the research starts a theoretic challenge of deconstruct or reconstruct our modern only habitational template, which is used today in all families configurations which out any regards to where this template will be used, unfitting to the intergenerational families who have elders. This study is then meant to give an differential analysis of the various domestic space’s templates in regards to the new families formats, their basic and special necessities, the home identities of those families which indicates the differential gap in housing and lifestyle from the higher social classes in comparison to the lower social classes. The interdisciplinary method was chosen in order to describe arrangements found in the lifestyles and the ways of cohabitation of the intergenerational families, this method is used for its knowledge base that better articulates the procedure method and the inductive reflexive approach made possible after an qualitative research. In order to accomplish that, an geographical space which tow real possibilities was selected, that is, the space where the people of great social and anthropological proximity are concentrated and the people which are the researcher kinships and friends, in between those are the habitants of Capim Macio’s, Candelária’s, Tirol’s and Petrópolis’s, neighborhoods, located in the south west zone of her home city Natal. It has been noticed that, meanwhile these intergenerational spaces do not claim their said spaces, because of their habits, necessities and relations in between generations and gender, their arrangements of said space are extremely creative. That means that alterations in the concepts of planning, construction and utilization of built spaces are imperative.

Pirometamorfismo em calcários da formação Jandaíra, bacia potiguar, nordeste do Brasil

The present study aims the characterization of thermally affected carbonate rocks from Jandaíra Formation in contact with Paleogene and Neogene basic intrusions in the region of the Pedro Avelino and Jandaíra municipalities (RN), northeastern Brazil. For this study, field, petrographic, x-ray diffraction, electron microprobe, and whole rock litogeochemistry data of carbonates were undertaken. The thermally unaffected limestones are classified like wackstones, grainstones and packstones. They may constitute carbonates grains of benthic foraminifera, echinoderm spines, ostracods, algae, corals, bivalves, gastropods, peloids and intraclasts. The porosities are classified like vug, intraparticle, interparticle, intercrystal and moldic types. The major minerals are calcite, ankerite and dolomite; the detrital are montmorillonite, pyrite, limonite, quartz and microcline. The thermally affected limestones are very coarse to very fine-grained and light to dark gray color. The fossiliferous components totally disappear, and the porosity tends to disappear. With the data obtained, it can be inferred that the carbonate protoliths would be calciferous to dolomitic limestones, both with small amount of clay minerals. Crystalline carbonates from dolomitic protolith have rhombohedral calcite and iron oxides / hydroxides, making the rocks much darker. The carbonates from calciferous protolith have a wide variation of grain size according to the recrystallization degree, increasing toward contact with the basic bodies. In this group, it was identified the minerals lizardite and spinel in weakly to moderately affected samples, and spinel and spurrite in strongly affected rocks, as well as calcite, that occur everywhere. The geological context (shallow level diabase intrusions), the crystallization of the pyrometamorphic minerals spurrite and olivine, and comparison with diagrams from the literature allow estimating temperatures and pressures around 1050-1200 °C and 0.5-1.0 kbar, respectively, for PTOTAL=PCO2. The post-intrusion cooling would have afforded the releasing of metasomatic / hydrothermal fluids, allowing the opening of the metamorphic system, with possible contribution of chemical elements from host units (sandstones, shales) and from basic intrusions. This would induce hydration of previous phases, allowing the formation of serpentine, chlorite and brucite. The results discussed here reveal the strong influence of the heat from basic intrusions within the sedimentary pile. Whereas in the offshore portion of the basin occur sills with up to 1000 m thickness, the understanding of pyrometamorphism might be useful for understanding and measuring the thermally affected rocks.

Pirometamorfismo em calcários da formação Jandaíra, bacia potiguar, nordeste do Brasil

The present study aims the characterization of thermally affected carbonate rocks from Jandaíra Formation in contact with Paleogene and Neogene basic intrusions in the region of the Pedro Avelino and Jandaíra municipalities (RN), northeastern Brazil. For this study, field, petrographic, x-ray diffraction, electron microprobe, and whole rock litogeochemistry data of carbonates were undertaken. The thermally unaffected limestones are classified like wackstones, grainstones and packstones. They may constitute carbonates grains of benthic foraminifera, echinoderm spines, ostracods, algae, corals, bivalves, gastropods, peloids and intraclasts. The porosities are classified like vug, intraparticle, interparticle, intercrystal and moldic types. The major minerals are calcite, ankerite and dolomite; the detrital are montmorillonite, pyrite, limonite, quartz and microcline. The thermally affected limestones are very coarse to very fine-grained and light to dark gray color. The fossiliferous components totally disappear, and the porosity tends to disappear. With the data obtained, it can be inferred that the carbonate protoliths would be calciferous to dolomitic limestones, both with small amount of clay minerals. Crystalline carbonates from dolomitic protolith have rhombohedral calcite and iron oxides / hydroxides, making the rocks much darker. The carbonates from calciferous protolith have a wide variation of grain size according to the recrystallization degree, increasing toward contact with the basic bodies. In this group, it was identified the minerals lizardite and spinel in weakly to moderately affected samples, and spinel and spurrite in strongly affected rocks, as well as calcite, that occur everywhere. The geological context (shallow level diabase intrusions), the crystallization of the pyrometamorphic minerals spurrite and olivine, and comparison with diagrams from the literature allow estimating temperatures and pressures around 1050-1200 °C and 0.5-1.0 kbar, respectively, for PTOTAL=PCO2. The post-intrusion cooling would have afforded the releasing of metasomatic / hydrothermal fluids, allowing the opening of the metamorphic system, with possible contribution of chemical elements from host units (sandstones, shales) and from basic intrusions. This would induce hydration of previous phases, allowing the formation of serpentine, chlorite and brucite. The results discussed here reveal the strong influence of the heat from basic intrusions within the sedimentary pile. Whereas in the offshore portion of the basin occur sills with up to 1000 m thickness, the understanding of pyrometamorphism might be useful for understanding and measuring the thermally affected rocks.

Análise estratigráfica da sequência mesodevoniana-eocarbonífera da Bacia do Parnaíba, nordeste do Brasil

The Middle Devonian-Early Carboniferous sequence of the Parnaíba Basin, lithostratigraphically defined as Canindé Group, has been reinterpreted using the basic model of sequence stratigraphy. Therefore, lithology and gamma ray well-logs and seismic lines of central portion of the basin were analyzed, producing up from there diagrams 1D, isochore maps and stratigraphic sections. As results of this study, were defined two depositional cycles of second order, referred as Depositional Sequence 1 (SEQ1) and the Depositional Sequence 2 (SEQ2). The SEQ1, with interval about 37 Ma, is limited below by Early Devonian Unconformity and is equivalent to the formations Itaim, Pimenteiras and Cabeças. The SEQ2, which follows, comprises a range of about 15 Ma and is equivalent to the Longá Formation The SEQ1 starts with the lowstand systems tract, consisting of progradational parasequence set in the basal part, predominantly pelitic, deposited on a prodelta under influence of storms and the upper part consists in sandstones of deltaic front, with the maximum regressive surface on the upper limit. The transgressive systems tract, deposited above, is characterized by retrogradacional parasequence set composed of shallow shelf mudstones, deposited under storm conditions. The maximum flooding surface, upper limit of this tract, is positioned in a shale level whose radioactivity in gammaray well-log is close to 150 API. The highstand systems tract presents progradational parasequence set, comprising mudstones and sandstones deposited in shelf, fluvial-estuarine or deltaic and periglacial environments, with the upper limit the Late Devonian Unconformity. The SEQ2 was deposited in shelf environment, starting with the lowstand systems tract, that is characterized by a progradational parasequence set, followed by the transgressive systems tract, with retrogradational character. The upper limit of the tract corresponding to the fusion between maximum flooding surface with the upper limit of this sequence, which is the Early Carboniferous Unconformity, where the overlapping section was eroded. This section, which corresponds the highstand systems tract is restricted to portions at which the erosion that generate the Early-Carboniferous Unconformity was less effective, preserving the records of this unit.